Dynamic Analysis of a Prestressed Concrete Railway Bridge Considering Cyclic Fatigue Load due to Railway Traffic

Resumo

The dynamic interaction between railway train composition, track, and bridge considering increased
deflections under fatigue loading is realized through computational analyses. The twenty five equations of
motion of three dimensional railway vehicle are obtained through dynamic equilibrium. The railway train
composition model is obtained by the eight vehicle’s association. The railway track irregularities are represented
by harmonic functions. The mechanic contact between wheels and rails model is based on Hertz, Kalker,
Coulomb, Vermeulen and Johnson’s theories. The rails are modeled with Euler-Bernoulli beam’s. The sleepers
and the ballast are modeled with spring-damper systems. The railway bridge structure in prestressed concrete is
mainly composed by two simply supported I-beams, which are represented with three-dimensional frame
elements based on the Euler-Bernoulli assumption. The Rayleigh’s method is used in structural damping. The
equations of motion of structural systems are implemented in Matlab software. Static analyses are presented
considering vertical deflections due to permanent load and prestress effects. Dynamic analyses are presented
considering the displacements of the sleepers, the ballast and the bridge. Results of vertical deflections
considering cyclic load fatigue influences at the reinforced concrete beams are presented and analyzed.